Merge branch 'sctp_sysctl'

Wang Weidong says:

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sctp: fix kfree static array pointer in sctp_sysctl_net_unregister

patch #1 revert the efb842c4("sctp: optimize the sctp_sysctl_net_register")
patch #2 add a checking for sctp_sysctl_net_register
====================

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>